There are on-vehicle information terminals in the known art, that have navigation functions including a function for displaying a road map of an area around the current vehicle position, a function for determining a recommended route from a start point to a destination through arithmetic operation and a function for providing route guidance based upon the recommended route determined through the arithmetic operation.
Such an on-vehicle information terminal includes a navigation circuit board. The navigation circuit board is achieved by mounting on a single multilayer printed board a plurality of low-frequency electronic components such as a power circuit, a gyro, a GPS circuit and a plurality of high-frequency electronic components such as a CPU chip, a memory chip and a graphics chip.
Since the navigation specifications vary among different vehicle models, the navigation circuit board is designed and manufactured in conformance to each set of specifications in the related art. This means a great length of time must be spent in the design stage to result in high production costs, and it is naturally more desirable to use fewer types of more versatile navigation circuit boards. Such a need is not unique to navigation circuit boards, but it is a common concern pertaining to all types of information terminals including on-vehicle information terminals, in which a given function needs to be altered for different models.
The present invention provides a circuit board structure to be adopted in an information apparatus that eliminates the need to design and manufacture the circuit board from scratch for each set of specifications.